Composite flexible porous sheet material



Nov. 26, 1968 H. H. SMITH 3,413,180

COMPOSITE FLEXIBLE POROUS SHEET MATERIAL Filed June 12. 1964 G 3 a m/01%United States Patent "ice 3,413,180 COMPOSITE FLEXIBLE POROUS SHEETABSTRACT OF THE DISCLOSURE A porous metallized fabric is disclosed whichconsists of a porous basic fabric having adhering to one surface thereofa thin sheet of metal which conforms to the surface contours of thebasic fabric. The metal sheet is ruptured at. a suthcient number of theinterstices of the basic fabric to give the required degree of porosity.The ruptured parts of the metal sheet extend inwardly of the respectiveinterstices to conform to the wall contours thereof. A sheet ofresilient material is bonded to the metallized fabric to produce acomposite sheet with flexing properties which substantially reduce anytendency for the metal sheet to be locally displaced.

This invention concerns metallised fabrics.

Metallised fabrics are known, and have been used for various purposes.For example, metallised fabrics have been made by securing a continuousmetal foil to a textile fabric by means of a suitable adhesive.Metallised fabrics have also been made by spraying textile fabrics withflaked metal particles suspended in a solution of a film-formingpolymer. It is also known how to produce a metallised textile fabric byevaporating metal onto the cloth in vacuo. All these prior fabrics andproposals however suffer from disadvantages. One use for metallisedfabrics is to afford protection for persons subject to substantialthermal radiation, and whilst a continuous metal foil, for example ofaluminum has a very high reflectivity for such radiation, it is notporous and seriously interfers with the evaporation of water from theskin of the wearer. For this reason, clothing made from such metallisedfabrics is not satisfactory as a protection from excessive themalradiation if worn for other than very short periods. Again, metallisedfabrics made by spraying textile fabrics with flaked aluminuim particlessuspended in a film-forming polymer have been found to have anemissivity for longwave infra-red radiation 'which is too high for manypurposes. It does not appear that coatings of metal evaporated ontohydrophilic textile fibres are stable to moisture.

It has also been proposed to strengthen a metal foil by the applicationthereto of a woven or unwoven fabric of textile material or wholly orpartly of wires, the foil and fabric being caused to adhere one to theother, with or without adhesive, by virtue of intimate contact producedbetween the foil and threads of the fabric by subjecting the foil toconsiderable pressure between the fabric and a layer of yieldablematerial such as rubber, said layer being a fiat web or the surfacelayer of a" pressure roll. The disclosure of the production and use ofsuch a strengthened foil makes no reference to the production of aperforate foil and since the purpose to which the strengthened foil wasto be applied, namely as a wrapping material for such as electricalconductors differs markedly from that of the material produced accordingto the present invention and quite different problems had to beconsidered, there is no reason to suppose that the strengthened foil is,in fact, perforate.

Patented Nov. 26, 1968 Recently, we developed a porous metallised fabricof the kind (hereinafter termed of the kind referred to) consisting of aporous basic fabric having adhering to at least one surface thereof, athin sheet of metal which conforms to the surface contours of the basicfabric, and which is ruptured at a suflicient number of the intersticesof the basic fabric to give the required degree of porosity, theruptured parts of the metal sheet extending inwardly of the respectiveinterstices to conform to the wall contours of the latter.

Such material may be made by causing the thin sheet of metal of adhereto at least one surface of the porous basic fabric by laying the sheeton the surface of the fabric and pressing into place by the directapplication thereto of a resiliently deformable material, wherein thepressure applied is sufficient to cause the sheet to conform to thesurface contours of the basic fabric and to rupture at a sufiicientnumber of the interstices of the fabric to give the required degree ofporosity, and the rutpured parts of the sheet to extend inwardly of therespective interstices to conform to the wall contour of the latter.

We have now found that there is a tendency in certain end uses wheresuch material is severely and continuously flexed or abraded, forlocalised disturbance and displacement of the metal sheet to occur. Thisdisadvantage is particularly noiticea-ble when the basic fabric isitself thin and more particularly when the basic fabric has lines offreedom therein, as for example, in some Woven textile fabrics.

It is an object of the present invention to produce a porous metallisedfabric, which overcomes, substantially, the disadvantage aforesaid.

The present invention is based on an appreciation of the possibility ofovercoming substantially the disadvantage aforesaid, by bonding a sheetof resilient material to the metallised fabric, the resilient sheethaving such thickness and properties as to produce a composite sheetwith flexing properties which substantially reduce the tendency forthemetal sheet to be locally disturbed or displaced.

Thus, according to the present invention a composite sheet materialcomprises at least one layer of porous metallised fabric of Pthe kindreferred to and at least one sheet of resilient material, which isbonded thereto over at least one surfacethereof, said resilient sheethaving such thickness and properties as to modify the effect of flexingthe composite sheet to an extent which is sufficient to reducesubstantially the tendency for the metal sheet to be locally disturbedor displaced from the basic fabric when the composite sheet is flexed.

According to a preferred feature of the invention said resilientmaterial is porous.

According to a further preferred feature of the invention, said porousresilient material comprises a natural or synthetic foamed plasticmaterial of a kind having interconnected cells.

Preferably, when the metallised fabric comprises a basic fabric and asingle thin metal sheet, the porous resilient sheet is bonded thereto onthe face of the basic fabric remote from the metal sheet.

These and further features of the invention will be apparent from thefollowing description, which concerns, by way of example only, theproduction of one form of composite sheet embodying the invention.

Of the drawings:

FIG. 1 shows a cross-section through the composite sheet;

FIG. 2 shows a schematic diagram of the apparatus used for theproduction of the composite sheet of FIG. 1; and

FIG. 3 shows a cross-section through a modification of the compositesheet.

Referring now to FIG. 1, the composite sheet comprises a basic fabricconsisting of a woven continuous filament viscose rayon weighing two anda half ounces per square yard, an aluminium foil 11 having a thicknessof 0.00025 inch, and a foamed polyester sheet 12 having a thickness ofone sixteenth of an inch. The three layers 10 to 12 are bonded togetherat their interfaces by suitable adhesive compositions, and the aluminiumfoil 11 is ruptured at suflicient of the interstices of the basic fabric10 to give the composite sheet a desired porosity.

Referring now to FIG. 2, one manner for producing the composite sheetwill be described.

Use is made of a calender or mangle comprising a hard bowl or roller 16working against a bowl or roller 17 covered with moderately soft rubbere.g. 34 BS. degree hardness and of a thickness of about one sixteenth ofan inch. A continuous sheet of thin aluminum foil 11 is coated on oneface with a thin layer of an adhesive 18 by being drawn through a rollercoater mechanism 19 with doctor knife attachment 20 and is then fed intothe calender or mangle together with the fabric 10 to be coated, whichis also in continuous length. The uncoated face of the aluminium foil isin contact with the rubber-coated bowl or roller 17 of the calender ormangle and the coated face of the foil is in contact with one face ofthe fabric, the other face of the fabric being in contact with the hardbowl or roller 16 of the calender or mangle. If desired, the hard bowlor roller of the calender or mangle may be heated (for example byfeeding steam thereto) to assist in fixing the adhesive.

The aluminium foil 11 is thus bonded to the upper face of the fabric 10and is ruptured at the interstices thereof, by the pressure of therubber covered roller 17 a pressure of about 1.4 tons per square inchbeing applied to the foil and basic fabric at the mangle 16, 17 for thispurpose.

The basic fabric with the foil bonded thereto is then passed through afurther roller coater mechanism 21 where the face of the basic fabric 10remote from the foil 11 is coated with adhesive 22. A polyester foamsheet 12 is then brought into pressurized engagement with the coatedface of the basic fabric 10 and is bonded thereto by calender rolls 23.

The composite sheet which emerges from the calenders 23 may be subjectedto drying or other after treatment to fix the adhesives if desired ornecessary.

The composite sheet described and produced by the method indicatedretains the remarkable properties of our metallised fabrics of the kindreferred to but can be continuously and severely flexed without anyappreciable tendency for the aluminium foil to be disturbed or displacedfrom the surface of the basic fabric.

It will be appreciated that it is not intended to limit the scope of theinvention to the above examples only, many variations, such as mightreadily occur to one skilled in the art being possible without departingfrom the principles of the invention.

Thus, for example, the metal may be bonded to the basic fabric by othermeans, and the metal may be applied to both sides of the basic fabric ifdesired. The metal may be other than aluminium, and the basic fabric maybe of other form and/or of other material. The resilient layer whichneed not be porous may be of different material, for example,polyurethane foam, and two layers of such may be incorporated in thecomposite sheet if desired. In addition, a backing fabric for outwardlydirect surfaces of the resilient layer or layers may be provided ifdesired. This latter modification is shown in FIG. 3

4 which is similar to FIG. 1 with the addition of the backing fabric 24.

It is envisaged that composite sheets according to the invention willfind many uses, in the production of for example, special protectiveclothing including space-suits, rainwear and other more conventionalgarments, shoes, tents and other camping equipment, cinematographscreens, electrical and electronic components and equip ment, radarequipment, building sheets such as wall coverings, and so on.

It will be appreciated that the composite sheet when formed with a layerof foam has good heat reflecting properties as well as low heatconduction properties, making use as a thermal insulating materialparticularly attractive for certain application.

The various layers of the composite sheet may of course be bonded attheir interfaces other than by use of adhesive compositions. Thus, forexample, a polyester foam layer may be bonded to a textile fabric by aheating technique or by other known processes.

I claim:

1. A composite flexible porous sheet material for use in an article ofprotecting clothing comprising at least one layer of porous metallizedfabric consisting of a porous basic fabric having adherent to at leastone surface thereof a thin sheet of metal, the basic fabric having aplurality of interstices to impart porosity to said fabric, said thinsheet of metalconforming to the surface contours of the basic fabric andbeing ruptured at at least a substantial number of said interstices ofthe basic fabric to give said metallized fabric porosity, the rupturedparts of the metal sheets extending inwardly of the respectiveinterstices to conform to the wall contours of the interstices, and atleast one sheet of porous resilient material having interconnected cellsand being selected from the group consisting of natural and syntheticfoamed plastic materials, said resilient material being bonded to saidporous metallized fabric on the face of the basic fabric opposite saidmetal sheet whereby said thin sheet of metal resists being locallydisturbed or displaced from said basic fabric when the composite sheetis flexed.

2. A composite sheet material according to claim 1 wherein said foamedmaterial consists of a polyester foam.

3. A composite sheet material according to claim 1 including a sheet oftextile fabric which is bonded to the surface of said resilient materialopposite said basic fabric.

4. A composite sheet material according to claim 1 wherein said thinmetal sheet consists of aluminium.

5. A composite sheet material according to claim 4 wherein said metalsheet is about 0.00025 of an inch thick.

References Cited UNITED STATES PATENTS 2,003,494 6/1935 Reynolds 161-1142,492,143 12/1949 Gipple etal 51-195 2,728,702 12/1955 Simon et a1.161-213 x 2,961,418 11/1960 Wilson et a1. 260-25 3,034,940 5/1962Collins 8! al. 161-89 3,240,855 3/1966 Voelker 156-254x FOREIGN PATENTS804,187 11/1958 Great Britain.

ROBERT F. BURNETT, Primary Examiner.

R. L. MAY, Assistant Examiner.

